bootstrap-salt.sh -h fails with "./bootstrap-salt.sh: 315: BS_TMP_DIR: parameter not set"

[jsbiff]

When invoking bootstrap-salt.sh with the -h flag to get usage help, depending on the version of bash installed, you will get an error, either:

/bootstrap-salt.sh: line 315: BS_TMP_DIR: unbound variable

or

./bootstrap-salt.sh: 315: BS_TMP_DIR: parameter not set

The root cause is that on line 372, which is part of the usage text, there is an attempt to expand BS_TMP_DIR. However, unless the user explcitly sets this on the command line, that variable is not set.

Rather, on line 249, the value of BS_TMP_DIR, if provided, is used to initialize variable _TMP_DIR, and if not set, _TMP_DIR is initialized to the default value, '/tmp', which appears to be used everywhere else in the file.

So I think the error here is that the usage text should NOT reference BS_TMP_DIR, but instead _TMP_DIR.